Efforts have been made in recent years to reduce operation noise and the like during a brake hydraulic pressure control such as ABS control. For this purpose, a rotary pump such as a trochoid pump is used in a vehicular brake device as a pump for the brake hydraulic pressure control.
A vehicular brake device having such a rotary pump is proposed in Japanese Patent Publication No. 2001-80498. FIG. 5 is a cross sectional view of a pump body J100 of a rotary pump that is provided in the vehicular brake device described in this publication.
As shown in FIG. 5, the pump body J100 is a unit in which two rotary pumps J10 and J13, as well as a drive shaft J54 for the rotary pumps J10 and J13 and the like, are incorporated in cylindrical cases J71a to 71d, J72a, and J72b. The pump body J100 constructed as the unit is also fixed to a housing J150 of the vehicular brake device. More specifically, the pump body J100 is inserted into a concave portion J150a of the housing J150.
In this case, a strong axial force is required in order to prevent the pump body J100 from wobbling in the housing J150 because of a high brake hydraulic pressure generated by intake and discharge of brake fluid.
However, considerable variations in the axial force may occur when the above axial force is generated by thread fastening. A leaf spring J210 is located as a countermeasure against this problem at an end or base position of the pump body J100. With this countermeasure it is possible to secure and stabilize the axial force of the pump body J100. At the same time, the axial force acting on the pump body J100 is also suppressed to the required minimum without becoming excessive.
However, a length in the axial direction of the pump body J100 becomes large in order to locate the leaf spring J210 at the end or the base position. As a consequence, the pump body J100 and accordingly the vehicular brake device cannot be made sufficiently compact.